Water Rocket Forum

Welcome to the Water Rocket Forum, sponsored by The Water Rocket Achievement World Record Association.

The largest, most sophisticated and ground breaking group supporting you, the serious water rocket flyer! Whether you are a beginner or an expert, the WRA2 has something for everyone.

A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.

The objective of this tutorial is to demonstrate how to build a completely new type of parachute ejection system for water rockets. This system was developed to fill the need for a reliable parachute ejection system that could be made from common materials which was very easy and fast to make. Historically, ease of assembly and reliability have been mutually exclusive goals. This prompted U.S. Water Rockets to take a "clean slate" approach to the problem. This tutorial will explain how to construct the latest version of the U.S. Water Rockets Axial Parachute Ejection System. This deployment system can be modified to be triggered using a tomy timer and does not require any electronics to function

After realizing its real hard work to repair a side deploy (not your Radial Deploy), I tried to build one, but modified it to use a tomy timer.

The mods are:

1. Instead of wavy lobes I made 5 " legs". It slides over the bottle. The benefits with this type of cone is less chance of premature deploys. It also increases band surface area (you can use smaller bands or in my situation, a chain of small bands)

2. No cone space. The legs' roots are 1 cm below the mold line. This increases ejection power. In connection with mod 1, it can also accommodate various sizes of chutes.

3. Free cone. Instead of tying the cone to the rocket, which in my case would be tied externally, I let the rocket fall down to earth without any recovery system. It also helps in timing-based altitude recording (Straton EX2 takes 3 secs to reach apogee - timer is set to 3 secs as well)